Abstract: A method for determining geometrical information about a medical treatment arrangement that includes a rotatable treatment radiation source unit is provided. The method includes attaching a phantom to a patient support of the medical treatment arrangement, attaching a calibration module to the rotatable treatment radiation source unit to permit the calibration module to rotate together with the rotatable treatment radiation source unit when the rotatable treatment radiation source unit is rotated, obtaining for each of a plurality of rotational positions of the rotatable treatment radiation source unit a projection image of the phantom and of the calibration module by an image detector, while a part of the calibration module is positioned in a radiation propagation zone between the rotatable treatment radiation source unit and the image detector, evaluating the images, obtaining an evaluation result, and determining geometrical information about the medical treatment arrangement from the evaluation result.

Abstract: An elliptical, optical-tracking marker comprises an inner marker body that is filled with radially spread color spectrum points with respect to a center point of the inner marker body. A color value of each spectrum point of the inner marker body is calculated as a function of an angle defined between a horizontal line crossing the central point of the inner marker body and a line crossing the central point of the inner marker as well as the given pixel in such a manner, that the color values of the respective spectrum points vary in accordance with a sinusoidal pattern along an elliptical path around the center point, in particular along a circular path centered around the center point. A method and a system for determining a 3D position of an object in space use the characteristics of this marker by detecting and analyzing the sinusoidal pattern.

Abstract: Three-dimensional image data of an imaged object, such as the bone structure of a patient, comprise first and second rigid parts movably connected to each other, in a first state of position and orientation. Sub-regions within the three-dimensional image data are divided into at least first image data and second image data. A set of two-dimensional projection images of the imaged object are taken from first and second different projection directions, while the first and the second rigid parts are in a second state of position and orientation. A processing device registers the first image data with the set of two-dimensional projection images and separately registers the second image data with the set of two-dimensional projection images to obtain first and second registration information, respectively, which is used to determine the position and orientation of the first and second rigid parts in the second state.

Abstract: A phased microphone array capable of being placed in the free stream flow of a wind tunnel test section. The array consists of a plane of microphones on arms radiating out from a central hub. Microphones are placed along the length of the arms. The array is to be fastened to an articulated mount which allows it to be repositioned and be placed in a number of viewing positions. The ideal arms are symmetric airfoils that rotate about the longitudinal axis of the arm so that in free flow the airfoils point into the oncoming flow. Microphones placed at the leading edge will be located at stagnation points decreasing wind turbulence and boundary layer effects.

Abstract: Functional beamforming is a vast improvement over classical beamforming methods. Let v be a power greater than unity. The v-th root of the array cross spectral matrix is computed and used in classical beamforming. The v-th power of the resulting beamform map is then computed. This procedure significantly reduced sidelobes, increasing the dynamic range of the results. Assuming the standard model of an incoherent source distribution, it is shown that the computed map values are greater than or equal to the underlying source strengths. Increasing v decreases the map values, steadily reducing sidelobes and peak widths. Quantitative component spectra can be computed by integrating the maps over regions of interest without the errors caused by sidelobes when integrating classical maps. Deconvolution processing is unnecessary. The time and other computer resources required for the computation are virtually identical to classical beamforming.

Abstract: A phased microphone imaging array and repeatable sound source are used in concert to determine absorption and reflection coefficients of materials and spaces across a continuous frequency domain. Coefficients can be determined at normal and oblique incidences to the surface using beamforming software. The invention can be used in-situ without needing to alter the environment in which it is testing. Accurate results can be obtained at any distance from the array and sound source to the testing surface with relatively little material.